Blowdown method for a coil-type cleaning machine



J. F. MALSBARY 2,530,710

BLOYFDOWN METHOD FOR A COIL-TYPE CLEANING MACHINE Nov. 21, 1950' Filed Oct. 27, 1945 A TTORNEK Patented Nov. 21, 1950 BLOWDOWN METHOD FOR A COIL-TYPE CLEANING MACHINE Job F. Malsbary, Oakland, Calif., assignor, by diroot and mesne assignments, to Malsbary Manufacturing Company, Oakland, Calif., a corporation of California Application October 27, 1943, Serial No. 507,791

1 Claim.

The present invention relates to improvements in a blow-down method for a coil-type cleaning machine, and has particular reference to a cleaning machine such as illustrated and described in Patent No. 2,295,228, issued to Walter W. Taylor and myself, as co-inventors.

In the above-mentioned patent it Was proposed to utilize a coil arranged above a, heater, a high-pressure pump for pumping a cleaning solution through the coil from top to bottom with a metering valve disposed at the coil intake and a hose with a discharge nozzle attached to the coil outlet for producing a wide range of different types of cleaning sprays. A suitable thermostat control was provided at the lower end of the coil for controlling the temperatures of the solutions.

In the present invention it is proposed to provide, in combination with the said cleaning machine, a method of and means for blowing down the coil for removal of scale and sediment forming in the coil windings, whereby the coil may be cleaned conveniently by the mere adjustment of a few valves forming part of the machine.

It is further proposed to provide means for blowing down the coil involving a mere reversal of the flow of liquid through the coil. While in the normal operation of the machine the cleaning solution is admitted at the upper end of the coil and is fed downward from a relatively cool zone to'the hottest zone at the lower end of the coil, it is proposed, for the blowing down of the coil, to feed the liquid from the lower end and to use a relatively limited flow, whereby the liquid is turnedinto high-pressure steam immediately upon its entry into the coil and the steam thus formed is forced through the coil at high velocity to blow off any scale or sediment that may have accumulated in the coil.

It is a further object of my invention to use a method for blowing down the coil, whereby the lower end of the latter may first be heated to a desired temperature, before the liquid is admitted to induce cracking and loosening of the scale and to make a higher degree of heat available for the immediate vaporization of the liquid.

Further objects and advantages of my invention will appear as the specification proceeds and the novel features of the same will be fully set forth in the claims hereto attached.

The preferred form of my'invention is illustrated in the accompanying drawing in which the one figure shown illustrates diagrammatically a cleaning machine having my invention incorporated therein.

While I have shown only the preferred form of my invention, I wish to have it understood that various changes or modifications may be made within the scope of the claims hereto attached, without departing from the spirit of the invention.

Referring to the drawing in detail, my cleaning machine, in its general features, may be constructed substantially along the same lines as that illustrated and described in the above-mentioned patent, except for the changes necessitated by the incorporation of the present invention.

In its principal features the apparatus comprises two containers land 2, a high-pressure pump 3 for pumping a liquid from the container through a coil 4, heating means 5 for the coil, an outlet nozzle 6 for the coil, and suitable control. means which will be discussed in their special relationships as the specification proceeds.

The container l is intended to accommodate a soap solution or other chemical or cleansing agent, and it receives its water supply from the pipe I, a float-control insuring a constant-level shut-off of the liquid in the container.

The container 2 is intended to accommodate Water and is also fed from the pipe l and provided with a suitable float control 9 for maintaining a desired water level. Valves l8 and H are provided for shutting off the supply going to the containers.

Both containers are provided with outlet pipes when the liquids are recirculated and a pressure exists within the pump passages and chambers.

The pipe l5 connects to the intake side of the high pressure pump 3 which may be operated by the motor I9, and which discharges, through the delivery valve 16, into the pipe 20. The lat ter, which is preferably provided with a compression chamber 2| for absorbing fluctuations and surges due to the pump action, and with a pres sure gauge 22, divides into two branches a and b which are connected to the top and bottom end of the coil 4 respectively.

The'branch a joins the upper end of thecoll through a T-joint shown at c, and the end of the coil is extended beyond the coil, as at d, this extension which leads to the atmosphere or a sewer having a valve e therein. The branch a, ahead of the T-joint, is provided with a valve j, which may be in theform of a metering valve, as shown in the patent referred to, or of a pressure-responsive regulating valve as disclosed in the co-pending application, Serial Number 440,314, Patent Number 2,345,614, filed by the same inventors, or of any suitable form depending upon characteristics desired of the machine as a whole.

For the purposes of the present invention, it is necessary that the valve, whatever its func--' tion during the normal operation of the machine, be adapted to serve as a shut-off valve when it is desired to blow down the coil.

The branch b connects with the lower end of the coil, preferably at the thermostat to be described hereinafter, and is furnished with a shut-off valve g.

The pump is intended to have a sufiicient capacity for providing a pressure, which under any circumstances of adjustment exceeds the pressure and volume required in the coil, and I therefore provide a by-pass pipe 2'! to connect pipes 13 and 2B and to provide a circulatory path 2i)27l3-l5, permitting a portion of the mixture ejected from the pump to re-enter at the intake'and to thereby cause additional agitationand more perfect mixing of the solution. The effective by-pass area may be controlled by a valve 28. 1

The coil 4 is suitably mounted in a housing 39,-

and a heater is mountedunderneath the coil,

the latter being arranged so that in normal operation theliquid flows downward in the coil toward theheater and is thus progressively subjected to increasing heat as it advances.

On the other hand, for blowing down operations,.the liquid is admitted at the lower end of the coil, preferably in a slow stream, which evaporates immediately and causes the steam to pass through the coil in a reverse direction at a very high velocity.

The-heater is here shown as a gas burner, but it is apparent that an oil burner or any suitable sourceof heat-might besubstituted. The details:- of the. heater and the thermostat control" for the same have been fully illustrated and described-in the patent above-referred to, and will be only briefly repeated in the prevent application to facilitate the understanding of the present. invention.

The main gas line is indicated at 3! and con-' nects, through a valve 32, the lower chamber of a housing 34, and the pipe 31, with the burner 5.- Th'efhousing 34 is divided, by a diaphragm, into. anzupperand a lower chamber, the diaphragm having a small orifice allowing of limited communication between the chambers adapted to establish an equilibrium of pressures as long as the upper chamber is kept closed. The diaphragm operates a valve below the diaphragm which'controls the flow of gas into the pipe 31.

An outlet pipe 41 from .the upper chamber above the diaphragm leads to the burner, as at 42, and is controlled by a valve 43, which latter is operated by a thermostat including an .Invar rod extending into the lower end 4'! of the coil Whichflower end. extends diametrically across the coil. The operative length of the Invar rod may-pesadjustedeby means :of a handle 56, where* by the thermostat may be adjusted to respond to different temperatures.

Thus, with the handle 56 set for a certain temperature, when the heat about the lower end of the coil drops below the set temperature, the thermostat .opens the valve 43, relieving the pressure'in the upper chamber of the housing 34 whereby the pressure in the lower chamber increases the valve opening so as to allow more gas to be fed to the burner.

When the temperature rise above the desired degree, the thermostat closes the valve 43, thereby causing the'pressures in the upper and lower chambers of the housing to become balanced and reducing the amount of gas fed to the burner.

A conventional pilot burner 44 may be connected to the maingas supply 3| ahead of the valve 32, through pipe 45 having a pilot valve 46.

The outlet pipe Q8 from the coil connects with a pipe 58 which latter is provided with a thermometer 59 and a pressure gauge 69 and connects with a hose 6| having the nozzle 6 at the'end.

thereof. A suitable handhold 62 i furnished near the nozzle, and a conventional shut-ofi valve 63 i located in the pipe 58.

The nozzle 6 is fully described in the patent above "referred to and 01 the purposes of the present application, it may be suificient to say that it contains a restricted orifice member which is exchangeable and the size of which is instrumental in controlling the pressure in the coil and character of the stream to be ejected.

To relieve excess pressure in the coil 4, I provide a pipe connection 10 having a pressure relief valve H discharging into the tank or container l. The pipe "#0 may also beconnected to the container 5 through a pipe 12 leading to the bottom portion of the container and being controlled by a valve E3. This connectionis used when it is desired to agitate the solution or to stir a new mixture. of a valve T1.

In the normal operation of the machine, for cleaning tanks, trucks, tractors, automobiles and the like, the valves g (in branch pipe b) and e (in the outlet pipe :1) are closed, and the valve f (in branch pipe a) and 63 (in the outlet pipe 55) are open, the valve 1 being adjusted to admit the desired amount of solution and to cooperate with the thermostat and the discharge nozzle to pro duce the desired spray, which may be made to vary through a wide ran e, from a hard-hitting solid stream of hot or cold liquid to superheated steam, as has been fully described in the patent referred to.

The operation of the present invention may be described as follows:

When it is desired to blow down the. cell for removal of scale and sediment, the valves and 63 are closed, and the valves g and e are opened.

The heater is then turned on to heat the coil from the bottom for vaporizing and driving out the water present in the coil and for dry-heatingv the lower end of the coil to a high temperature greatly in excess of normal operating temperatures. the scale due to the different co-efficients of expansion between the metal and the scale.

Next the pump is started and .the valve 5;

opened to admit a desired amount of water into the lower end of the coil. The water chills the coil which again is accompanied by a furthercracking and loosening of the scale duetothe:

different co-eificients of expansion.

At the same time the water explodes-into steam;

The pipe .13 may be closed by means- This causes a cracking and loosening of with tremendous force and the steam is forced through the coil at high velocity picking up the loosened scale at the lower end of the coil, and driving the scale through the remainder of the coil with a sandblasting effect, tearing off whatever forelgn particles may adhere to the coil in the upper end and thoroughly cleansing the entire coil.

I claim:

The method of blowing down a vertical coil having a heater underneath the same and having means for pumping a liquid therethrough from top to bottom, which comprises the steps of closing the coil against the pump and against discharge at the lower end, opening the upper end of the coil to the atmosphere, causing the heater to heat the coil for evaporating liquid present in the coil and for discharging the same into the atmosphere, continuing operation of the heater for heating the dry coilgreatly in excess of normal coil temperatures for cracking solids adhering to the inside of the coil, and forcing liquid from the pump into the lower end of the coil for suddenly chilling the same for additional cracking effect and for exploding the liquid into steam adapted to entrain loosened solids and to race the 6 same throughout the coil toward the atmosphere with a sandblasting effect for cleansing the coil.

JOB F. MALSBARY.

REFERENCES CITED I he following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 536,877 Kaemerling Apr. 2, 1895 685,624 Manley Oct. 29, 1901 1,078, 53 Carey et a1 Nov. 11, 1913 1,149,164 Richter Aug. 3, 1915 1,191,451 Morterud July 18, 1916 1,464,705 Goosman Aug. 14, 1923 1,568,440 Behringer Jan. 5, 1926 1,684,227 Johnson Sept. 11, 1928 1,701,824 Robinson Feb. 12, 1929 1,824,505 Schellens Sept. 22, 1931 2,295,228 Malsbary et a1 Sept. 8, 1942 FOREIGN PATENTS Number Country Date 468,576 France July 9, 1914 

